18d91cbadSRussell King /* 28d91cbadSRussell King * linux/drivers/acorn/char/i2c.c 38d91cbadSRussell King * 48d91cbadSRussell King * Copyright (C) 2000 Russell King 58d91cbadSRussell King * 68d91cbadSRussell King * This program is free software; you can redistribute it and/or modify 78d91cbadSRussell King * it under the terms of the GNU General Public License version 2 as 88d91cbadSRussell King * published by the Free Software Foundation. 98d91cbadSRussell King * 108d91cbadSRussell King * ARM IOC/IOMD i2c driver. 118d91cbadSRussell King * 128d91cbadSRussell King * On Acorn machines, the following i2c devices are on the bus: 138d91cbadSRussell King * - PCF8583 real time clock & static RAM 148d91cbadSRussell King */ 1566769330SPaul Gortmaker #include <linux/module.h> 168d91cbadSRussell King #include <linux/i2c.h> 178d91cbadSRussell King #include <linux/i2c-algo-bit.h> 1899730225SRussell King #include <linux/io.h> 198d91cbadSRussell King 20a09e64fbSRussell King #include <mach/hardware.h> 218d91cbadSRussell King #include <asm/hardware/ioc.h> 228d91cbadSRussell King 238d91cbadSRussell King #define FORCE_ONES 0xdc 248d91cbadSRussell King #define SCL 0x02 258d91cbadSRussell King #define SDA 0x01 268d91cbadSRussell King 278d91cbadSRussell King /* 288d91cbadSRussell King * We must preserve all non-i2c output bits in IOC_CONTROL. 298d91cbadSRussell King * Note also that we need to preserve the value of SCL and 308d91cbadSRussell King * SDA outputs as well (which may be different from the 318d91cbadSRussell King * values read back from IOC_CONTROL). 328d91cbadSRussell King */ 338d91cbadSRussell King static u_int force_ones; 348d91cbadSRussell King 358d91cbadSRussell King static void ioc_setscl(void *data, int state) 368d91cbadSRussell King { 378d91cbadSRussell King u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); 388d91cbadSRussell King u_int ones = force_ones; 398d91cbadSRussell King 408d91cbadSRussell King if (state) 418d91cbadSRussell King ones |= SCL; 428d91cbadSRussell King else 438d91cbadSRussell King ones &= ~SCL; 448d91cbadSRussell King 458d91cbadSRussell King force_ones = ones; 468d91cbadSRussell King 478d91cbadSRussell King ioc_writeb(ioc_control | ones, IOC_CONTROL); 488d91cbadSRussell King } 498d91cbadSRussell King 508d91cbadSRussell King static void ioc_setsda(void *data, int state) 518d91cbadSRussell King { 528d91cbadSRussell King u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); 538d91cbadSRussell King u_int ones = force_ones; 548d91cbadSRussell King 558d91cbadSRussell King if (state) 568d91cbadSRussell King ones |= SDA; 578d91cbadSRussell King else 588d91cbadSRussell King ones &= ~SDA; 598d91cbadSRussell King 608d91cbadSRussell King force_ones = ones; 618d91cbadSRussell King 628d91cbadSRussell King ioc_writeb(ioc_control | ones, IOC_CONTROL); 638d91cbadSRussell King } 648d91cbadSRussell King 658d91cbadSRussell King static int ioc_getscl(void *data) 668d91cbadSRussell King { 678d91cbadSRussell King return (ioc_readb(IOC_CONTROL) & SCL) != 0; 688d91cbadSRussell King } 698d91cbadSRussell King 708d91cbadSRussell King static int ioc_getsda(void *data) 718d91cbadSRussell King { 728d91cbadSRussell King return (ioc_readb(IOC_CONTROL) & SDA) != 0; 738d91cbadSRussell King } 748d91cbadSRussell King 758d91cbadSRussell King static struct i2c_algo_bit_data ioc_data = { 768d91cbadSRussell King .setsda = ioc_setsda, 778d91cbadSRussell King .setscl = ioc_setscl, 788d91cbadSRussell King .getsda = ioc_getsda, 798d91cbadSRussell King .getscl = ioc_getscl, 808d91cbadSRussell King .udelay = 80, 81082a4cf8SJean Delvare .timeout = HZ, 828d91cbadSRussell King }; 838d91cbadSRussell King 848d91cbadSRussell King static struct i2c_adapter ioc_ops = { 85531660efSRussell King .nr = 0, 868d91cbadSRussell King .algo_data = &ioc_data, 878d91cbadSRussell King }; 888d91cbadSRussell King 898d91cbadSRussell King static int __init i2c_ioc_init(void) 908d91cbadSRussell King { 918d91cbadSRussell King force_ones = FORCE_ONES | SCL | SDA; 928d91cbadSRussell King 93531660efSRussell King return i2c_bit_add_numbered_bus(&ioc_ops); 948d91cbadSRussell King } 958d91cbadSRussell King 962a9915c8SAl Viro module_init(i2c_ioc_init); 97